Well there is some truth to this, however it also pertains to pretty much ALL german cars. BMW, Mercedes, Audi, VW etc will all be on the high side of maint/mod costs.
The 2.7 Bi-turbo is known to be a maint heavy engine. Also, when coupled with the smaller A4 class, heat tends to be its worst nightmare killing turbos, seals and pretty much all rubber products because of the tiny engine bay. However in the larger A6 chassis, the 2.7T is much more reliable. They are not known to kill the turbo's, but the seals and rubber stuff still gets abused.
I am an Audi/VW guy all the way, so I would be looking for a B6 (2002-2005) A4 Avant 1.8T Quattro manual. They can be had for around 10k for the avant and under 10k for the sedan. Add a chip and injectors and you have a fun to drive daily driver.
For 10k you have a lot of choices.
Mustang GT
F-body
GTP
SRT-4
WRX
My list would be
MKIV(99-06) Jetta/GTI 1.8T/VR6
B6 A4 1.8TQM
You can also pick up a good B5 S4 sedan for around 10k, but as stated, they are very expensive to keep usually.